Chapter 3 Flashcards
Heredity
The biological process for passing on traits from generation to generation
Genes
-Basis of heredity
-Approx 20-25k
-Guide creation of proteins that make up our physical structures and regulate development and physiological processes
-Made of segments of DNA
Cell Breakdown
Cell-Nucleus-Chromosome-Genes-DNA
Chromosomes
-Structure in cell nucleus lined with genes someone inherits
-Humans have 23 pairs
-Same genes are found on both chromosomes inherited from mother and father
Genotype
-Genetic makeup of an organism
-Unique set of genes for individual’s genetic code
Phenotype
-Physical traits and behavioural characteristics expressed
-Shows genetic variation
Behavioural Genomics
-Study of DNA and how specific genes are related to behaviour
Human Genome Project
-Coordinated effort to identify and map the entire human genome (2003)
-Approx. 22 300 genes identified
-Allows us to link genotypes to behaviours
Behavioural Genetics
-How genes and environment influence behaviour
Twin Studies
-Monozygotic twins (100% genetically identical)
>Differences show weaker links between genes and behaviour
-Dizygotic
>Have similar environment
-Genetic related individuals tend to be more similar if trait is mostly genetically determined
Heritability
-How much do the genetic differences contribute to behaviour differences or traits within a population
-Tells us how genes explain the difference in the expression of a trait within a population; not how genes contribute to the trait itself
Ex. Having eyes-0 Eye Colour-0.80
Genetic and Environmental Influences Both Account For Differences In Behavior
Nature vs. Nurture : Genes versus environment
Adoption Studies
If children resemble adoptive parents ->environment
If children resemble biological parents
->genetic
Genes are Either
-Active(expressed) : Contribute to the production of proteins
-Inactive
Gene Expression/Activation
-Influenced by genetics, environmental factors
-Lifelong process
Epigenetics
-How experiences cause changes in gene expression without altering genetic code
Biopsychosocial Model
Behaviour—Environment—Genes
Altering Genes and Gene Expression
-CRISPR-Cas9
>Technique that allows genetic material to be removed, added or altered in target areas in the genome
Natural Selection
-Favourable traits becoming more common in interbreeding population, while less favourable traits become less common
Evolution
-Change in frequency of genes occurring in interbreeding population over generations
-Not continuous
-Never done (new environmental pressures)
Evolutionary Psychology
-Attempts to explain human behaviours based on beneficial functions they may have had in our species’ development
-planning
-problem solving
-direct attentional focus
-communication (symbolic representation)
Nervous System
-A system of nerves
-The part of the body involved in coordination of behaviour
-in invertebrates the nervous consists of
>CNS : Central Nervous System-brain and spinal cord
>PNS : Peripheral Nervous System- nervous connections throughout the body
Neurons
-Type of cell in nervous system
-Responsible for sending messages throughout the body
Structure of Neuron
Soma(Cell Body): Contains nucleus with genetic material
Dendrites: Small branches attached to soma that receive other cells’ messages
Axon: Transports info in form of electrochemical reactions from cell body
Axon Terminals: Bulb like extensions at axon end. Filled with vesicles containing neurotransmitters
Neural Communication
-Message circles back to initial neuron
-Feedback tells initial neuron to stop sending messages
Sensory Neurons
Sensory Information-> Brain (Afferent)
Motor Neurons
Brain->Muscles (Afferent)
Interneurons
-Communication between neurons (efferent)
-Important for reflexes : sensory -> muscle
Neurogenesis
Formation of new neurons
Neuroplasticity
Process by which brain changes and rewires itself based on experience
(Certain neural networks will ‘fortify’ while some will be forgotten)
Resting State(Resting Potential)
-Relatively stable state with no message transmission
-Higher concentration of positive ions outside neuron
-Negative ‘net charge’ inside the neuron
Ions like to be disturbed
-High to low concentration
Ion Channels
Small pores on neuron’s cell membrane, allows ions to pass through
When Stimulated
-Ion channels open
-Positive ions flow in (Negative charge -> positive charge)
-If positive charge reaches firing threshold, creates an action potential
Action Potential
Wave of electrical activity starting at start of axon (near soma) and rapidly travelling down the length of axon
After the Action Potential
-Ion channels close, allowing return to rest state
-Ion pumps get rid of positive ions
-Cell is hyperpolarized (extra negative)
-Refractory period where neuron can’t fire until returning to original resting potential
When Action Potential Reaches Axon Terminal…
Neurotransmitters are released into the synapse
Neurotransmitters
-Chemicals that function as messengers
-Allows neurons to communicate
-Stored in axon terminal vesicles
Synapse
-Area with presynaptic neuron axon terminals and post synaptic dendrites
-Separated by tiny space called synaptic cleft
Neurotransmitters From Presynaptic Neuron Influence Charge of Post Synaptic Neuron
-Excitatory: Increase positive charge >Increase likelihood for action potential
-Inhibitory: Decrease positive charge
>Decrease likelihood for action potential
Lock and Key Model
-Each neurotransmitter fits into a particular ‘post synaptic receptor’
Neurotransmitters are Released Back Into Synapse Where They Are
> Broken down by enzymes
Reuptaken: Reabsorbed into axon terminals of presynaptic neuron
Nervous System
CNS—Brain, Spinal Cord
PNS—ANS: Sympathetic
Parasympathetic
SNS
Peripheral Nervous System
-Transmits signals between the brain and rest of body
-Divided into 2 subcomponents
(Somatic, Autonomic)
Somatic System
-Nerves that control skeletal muscles, responsible for voluntary and reflexive movements
-Nerves that receive sensory input from body
Autonomic System
-Unconscious control of glands and bodily organs
>Sympathetic nervous system: Prepare body for action (flight or fight)
>Parasympathetic nervous system:
Maintain homeostasis, return to ground state
Two Hemispheres
Left and right brain
Hind Brain
Survival: Structures critical for basic life sustaining processes
Brain Stem:
>Medulla-Regulation of breathing,heart rate, etc (minimal conscious control)
>Pons-Wakefulness
Cerebellum: “Little Brain”
>Coordination and timing of movement, maintaining balance, attention and emotional responses
(fluid smooth movement)
Mid Brain: Sensation and Action
-Relay station between sensory and motor areas
-Superior Colliculus -> Orienting visual attention
-Inferior Colliculus -> Orienting auditory attention
Guiding, not processing
Forebrain: Everything above the midbrain
Interconnected structures critical to processing emotion, memory, thinking, and reasoning
Basal Ganglia:
Planned movements
Skilled learning
Integrating sensory and motor info with reward/pleasure system
Implicated in mood disorders
Amygdala:
Facilitates memory formation for emotional events
Mediates fear responses
Recognizing and interpreting emotional stimuli
Hippocampus:
Learning and formation of new memories
Hypothalamus:
Homeostasis (tempt,hunger,thirst,sex)
Thalamus:
Relays incoming sensory information to different brain regions
Cerebral Cortex
-Wrinkled outer layer of the brain (wrinkles = more surface area)
-Involved in ‘higher functions’ such as thought, language and personality
-Consists mostly of cell bodies and dendrites (grey matter)
-These neurons’ axons spread to different brain region (white matter)
The Cerebral Cortex (Four Lobes)
Occipital Lobes: Visual information
Parietal Lobes: Touch, bodily awareness, spatial awareness, attention
>Somatosensory cortex
Temporal Lobes: Hearing/language, memory, visual object recognition
Frontal: Higher cognitive function
-Primary motor cortex (voluntary movement)
-Prefrontal cortex (planning, decision making, attention, regulating impulses and emotions, language production)
Lesioning
-Intentional damaging to an area in the brain
-Allows researchers to isolate brain structures, lesion them, and then study resulting behaviour
Morris Water Maze
Used to measure spatial learning and navigation in rats
>Suggests hippocampus is important for this
Transcranial Magnetic Stimulation (TMS)
-Application of electromagnetic pulse to targeted region of the brain
-Pulse typically disrupts the natural brain activity at that region (disrupts flow of ions around the neuron)
-Induces a ‘temporary lesion’
-Can also be used to stimulate the targeted brain region (by applying a weaker pulse) and increase activity at the location
Computerized Tomography (CT Scan)
-X-rays are sent through the brain by a tube that rotates around the head
-Images show differences in tissue density (eg. grey matter vs. white matter vs. ventricles)
-Pictures taken at different positions reconstructed to create 3D images
Magnetic Resonance Imaging (MRI)
-A strong magnetic field causes protons in hydrogen atoms to spin in the same direction (alignment)
-A radio wave pulse is sent through the brain, knocking the atoms out of alignment
-When the radio wave is turned off, the atoms return to alignment, releasing the energy absorbed by the pulse
-Grey matter, white matter and fluid all release energy at different rates (which are measured)
Diffusion Tensor Imaging
Measures white matter pathways (axons) in the brain
Functional Neuroimaging
-A type of brain scanning that provides information about activity in the brain during a particular behaviour, or in response to a stimuli
-Potential trade-off between:
>Temporal resolution (how small/accurate a time period can be measured)
>Spatial resolution (how clear the image of the brain is)
Electroencephalogram(EEG)
-Measures patterns of brain activity (neuronal firing) using multiple electrodes attached to the scalp
-Measure Brain activity every millisecond (excellent temporal resolution)
-Limited spatial resolution, less effective at locating region of brain activity
Magnetoencephalography (MEG)
-Measures tiny magnetic fields created by the electrical activity of nerve cells in the brain
-Also measures brain activity every millisecond (excellent temporal resolution)
-Slightly better at localizing brain activity, but still not great spatial resolution
Positron Emission Tomography (PET)
-Radioactive substance is injected into the blood and its travel to regions of the brain engaged in a particular task are measured
-Increased blood flow (carrying oxygen) to brain regions that are more active -> Higher radioactivity will be measured in brain regions that are more active
-‘Radiotracers’ allow the measurement of certain neurotransmitter receptors
-Good spatial resolution, bad temporal resolution (>2 minutes)
Functional Magnetic Resonance Imaging (fMRI)
-Measures the amount of oxygen-rich blood flow into active brain regions
-This is called the BOLD (Blood, oxygen, level, dependent) response
-Not great temporal resolution (approx 2s)
oxygenated blood has different magnetic properties than deoxygenated blood
